Fish dying? Why?

[Jhirschboeck314]

I have a 20 gallon tank with 4 black neons, 3 balloon mollies, a swordtail a platt and some shrimp. I’ve had the tank set up for about 4 months. Everything was going well. I decided to start a planted tank so I added some Caribsea planted substrate. I got some plants that were packaged and went to town. Ever since then my fish have been mysteriously dying. I did a water test and nothing was different.
Ammonia-0
Nitrite-0
Nitrate-10
Ph-8

I did a 20% water change and left it about a week. Fish are still dying and I tested the water and it was still the above. I have a mollie and 3 black neons left. I’m assuming it’s somthing with the plants and substrate. I rinsed them very well. Any ideas?

 

[kno4te]

Hard to say but could be from the plants that were recently added. Normal practice should be to even treat ot quarantine the plants.

Was the plants in a tank with other fish? If so maybe the plants introduced something. Sorry for lossso far.

 

[Jhirschboeck314]

Hard to say but could be from the plants that were recently added. Normal practice should be to even treat ot quarantine the plants.

Was the plants in a tank with other fish? If so maybe the plants introduced something. Sorry for lossso far.

They were tubes with water gel and they weren’t with other fish. Do you suggest I just take them out? I do have an empty tank I can quarentine them in but it’s not done cycling

 

[AKKADIAN]

How many plants did you add to your tank? 20G is fairly small...it could be possible that during the night there is a lack of oxygen in the tank.

At night the plants are creating CO2 I believe. This is why in planted tanks it is important to run the air pumps more during the night.

 

[kno4te]

They were tubes with water gel and they weren’t with other fish. Do you suggest I just take them out? I do have an empty tank I can quarentine them in but it’s not done cycling

Well if it’s the plants then it maybe in ur tanks already. Would just watch and not add any fish. Consider making the tank a temporary qt tank.

 

[squint]

Are you using any liquid carbon products?

 

[skjl47]

added some Caribsea planted substrate.

Ever since then my fish have been mysteriously dying.

hello; the sequence of adding the substrate and having problems it the best clue so far. I have raised planted tanks for decades and nearly all the time I use some gravel only.
No experience with the substrate mentioned so cannot say much